They enlisted volunteers on treadmills and robots that stomped and swung mechanical legs. Neither stomping or swinging by themselves caused the knots to come untied.

But a combination of stomping and swinging did. Apparently stomping causes the knot to become tied less tightly so that slippage becomes possible in it. The swinging of the leg imparts lateral forces that pull on the laces. After enough of that a catastrophic failure ensues and the knot unravels very rapidly.

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Most shoelaces that loosen do so because they were tied in a Granny Knot instead of a Square knot. If you tie a square knot and wrap two turns around the standing loop instead of one, all that swinging and stomping will leave your shoes tied as before.

The Granny is what they are calling the "false knot", in the article.

Knot people say the reason the Granny comes loose easily is that the free tails are touching each other, run past each other, share a common "hole"so to speak. So the grip loops only touch each one on one side. As they work on each other, they work loose, initially by being jolted so they "squirm" in the catchment.

But I never tested that - it made sense looking at the knots, but I took the sense for granted. Now I've been scooped.